fix: no blue disc behind the sidebar profile picture

Keep the colored background only for the initials fallback; a real
photo fills the circle with a transparent backing.

frontend/editor/src/core/components/shared/FileSidebar.css

@@ -399,6 +399,11 @@
   overflow: hidden;
 }
 
+/* No colored disc behind an actual photo; keep it for the initials fallback. */
+.file-sidebar-bottom-avatar--picture {
+  background-color: transparent;
+}
+
 .file-sidebar-bottom-avatar-img {
   width: 100%;
   height: 100%;

frontend/editor/src/core/components/shared/FileSidebar.tsx

@@ -944,7 +944,9 @@ const FileSidebar = forwardRef<HTMLDivElement, FileSidebarProps>(
             style={onOpenSettings ? { cursor: "pointer" } : undefined}
           >
             <div
-              className="file-sidebar-bottom-avatar"
+              className={`file-sidebar-bottom-avatar${
+                showProfilePicture ? " file-sidebar-bottom-avatar--picture" : ""
+              }`}
               aria-label={displayName}
             >
               {showProfilePicture ? (